Heritage Hearthstone - heat output -damper?

[Dottie]

Hi, I hope that someone can give me some advice on this. This is my second season using my Heritage Hearthstone. I really like it and although it doesn't keep the house toasty warm, it stays warm enough for me. I just read in another link that the person was getting 650 to 750 degrees and that he was looking for a leak. I know that that is way too high for the Heritage, but I wonder if my stove is getting hot enough.

I have to leave the door cracked and the damper wide open to get it up to 350 degrees, then I close the door and damper down and it will "cruise" at about 300 or so. This seems too low according to other posts that I have read.

I had the chimney/installer guy, who seems very knowledgeable and honest, in to clean the chimney at the beginning of January. The stove had stopped drawing and was smoking. He said that the wire/mesh guard at the top of the chimney was covered in creosote, but he said the chimney was absolutely creosote free, just a little white ash. He said that because the chimney was high, that when the heat hit the guard, creosote covered the mesh and clogged in up. He took the guard off and said that it was fine to burn without it. I forget the name of the chimney liner, but it was a good one and guaranteed for life.

I ask him about installing a damper (I had ask when he installed the stove last year, as well), and he said that it would only cause trouble and why did I want one. Well, I couldn't think of a good answer, because I don't know why I would want one, I just don't think that the stove gets hot enough.

The stove is installed in front of a fireplace, its vented out the back of the stove, with a connector maybe 18 inches of so and then it goes up the chimney two floors and an attic, I'm not sure how high but maybe 30 feet or so. Does anyone have any ideas for me about a damper, or if this stove is getting hot enough?

Thank you.

Dottie

 

[Vic99]

The Heritage seems to be a good stove. When everything works right, you should easily hit 400F +.

In my opinion, the number one reason why people don't get the heat output they expect is because the wood is not dry enough.

Must be <20% moisture content. You can get a cheap moisture meter from Harbor Frieght (15-20 bucks). There are exceptions, and sometimes it depends on what part of the country you are in and what wood you are using, but typically wood takes ~1 year to season properly. Oak and rock maple 1.5-2 years for the larger splits.

For now, trying using small splits. Good luck.

 

[edthedawg]

I know I have wood moisture >20% and I still get the Heritage up to 500+ with a very similar-sounding setup to Dottie's (out the back, up thru 2 tall storeys + attic, ~35 ft to cap). Note: I use a damper to do this. I also carefully use some compressed / alternative products to supplement the wood supply. A good supply of small splits / large kindling ought to be able to perform a similar effect of producing a hot core fire source.

If the chimney is clean, that sounds like a good thing. The wood isn't buggering it up. The clogged mesh cap isn't a big shocker - seems to happen to lots of users. I assume the firebox is similarly not showing a heavy presence of black and/or glossy soot buildup?

Leaving the door cracked and damper wide open to get to 350 - how long does that take before closing the door and shutting the primary?

And do you close it and then shut the primary straight to full off? or do you slowly back it down?

Cruising at 300ish - seems too cold - is there a strong secondary burn going? how long does it stay burning w/ good secondaries? or does it go right out?

You should be able to reach 450+ on a top-center located Rutland thermometer (push it back as close as you can to the top casting without the magnet snapping onto the metal casting) on your second fire from stone cold. It really sounds like you are overdrafting & pulling all that good heat right out of the firebox. A properly used and installed damper can significantly improve this for you.

 

[Highbeam]

You are right that the heritage should be getting much hotter. I can contollably and purposely run my heritage up to 550 when I need max output and the heritage at 550 puts out much much more heat than a heritage at 300. So you'll need to solve your problem before you can make heat with your stove, you haven't seen half of what it can do.

I agree with vic that your issue is most likely wet or green wood. The next most likely cause is that your wood is not cut down enough into small enough splits. So for your next fire, split them down half as big as you are currently doing it. Then check for water hissing and bubbling out. When this stove has good wood you can shut the damper in stages to about one inch from closed to get the highest stove temps.

Your installer was probably right to remove that screen, mine is gone too. They plug up depsite the best practices. If your local laws require it to be there then removing it can be a liability issue.

 

[DAKSY]

I agree with EdtheDawg's last statement...
You're pulling too much out of the stove - overdraft - due to your chimney height.
You can verify this if you can get someone to hook up a draft meter
into your connector pipe while the stove is burning...
Put an in-line damper in the system & you'll get more heat outta your Heritage...
BTW, Max allowable chimney height for this unit is 30' per the install manual...

 

[Backwoods Savage]

Dottie, you would only need a damper if your stove was getting too much draft. As you stated, it sounds as if the opposite is true if you have to crack the door in order to get the fire going. No doubt removing that mesh in the cap will help.

I also agree with the other fellows in that is sounds as if your wood is not dry enough. So make sure for next year that you get your wood ready NOW! Get it split and stacked, preferable in the sun but for sure where wind will hit the side of the wood pile. Leave it uncovered. Do not cover it until late fall or early winter. This will allow for better evaporation of the moisture. Once you get some good dry wood you should be amazed at the difference.

Good luck.

 

[edthedawg]

I could see the draft being stubborn from dead cold. It'll take me a few minutes usually to get a good rip going, and I sometimes do leave the door cracked open to do this. But that's on the first load from cold. Subsequent reloads, I almost never have to do that.

Reload sequence:
Rake coals to the front, clear out the primary feed hole on the doghouse, pile bark scraps, chips, and kindling on top of the coals, big splits in the back down low, and smaller splits above and in front - right up and on top of the kindling pile.

For best results, I stick a Bio-Brick (two if it's really cold) or an EcoFirelog right in the middle of the pile.

Close the doors, set primary full open. Let it burst into flames (usually within seconds, longer if it's been a dormant coal pile) and then let that ride for awhile. It'll eventually go to a full flaming firebox - usually takes a few minutes. Then once at full rolling flames, no more than 15 minutes more til i close the damper and the primary. I try not to slam them both shut at the same time unless it's a well-established fire (or i'm hurrying out the door to work). On rare occasions, doing so will knock the fire down too low. Best results include at least a 5-10 minute mid-step w/ the primary and damper both about 3/4 of the way closed, then full-shut on both...

[Edit: I usually only go full shut on both when we're gone for the day. If we're home and enjoying the fire, I'll leave them both cracked open a bit, tho maybe not the aforementioned 3/4 setting...]

 

[Dottie]

Thank you all for your advice.

I think that the wood's ok, at least that's what the stove guy said when he looked at it, but it isn't in terribly small splits, I usually put about 3 largish ones (either split or rounds) and maybe 4-5 smaller ones after I get the fire going. It takes about 1 hour after the fire dies down to get it over 300 and then be able to damper it down, it does have a nice secondary burn. I try to do it gradually, but circumstances (like having to go to work), doesn't always allow for either of these things and I have to turn the damper all the way down as I'm gone most of the day, although I do come home at lunch to build up the fire, and turn it down again.

I will burn about 4-4 1/2 cords this winter and have 3 cords put by for next winter already. I don't have any more room for more as I live in town with a small lot, but if the fault is in the lack of dryness in the wood, I should be able to see the difference.

I'm lots better at keeping a fire going this year than last year and I can usually start the fire from the coals, sometimes just with wood and other times with a few pieces of fatwood and some paper twists, if it has really gotten too cold.

Could someone tell me exactly how a damper is supposed to work and what it does?

Thanks.

 

[edthedawg]

Dottie,

There is really something wrong with either your wood or your burning practices (sorry!) if you are starting from coals, burning high, letting it "die down", and THEN working another HOUR to keep building heat - and the whole time your stovetop temp is under 300??? I'm really sorry but that just ain't right. I took a small pile of coals this morning to 425 in the space of about 45 minutes. Built it just as described above, ran the flue damper and primary air both wide open w/ doors clamped shut for about a half hour, then went back and shut the flue damper and primary most of the way. After another 15-20, I closed them both. I wish I had had time this morning to top it off w/ 2 more splits right then - I had been trying to really heat it up, but alas - had to run off to work. Tuesdays are long days for us anyways - 12+ hours out of the house...

As for what a flue damper is - it's simple. It's just a cast flat plate that fits loosely inside your chimney pipe. It sits on a spindle w/ an external handle, so it can be adjusted freely.

(broken link removed to http://www.stovax.com/images/cms_prodpics/small/509_1.jpg)
A good image of a typical damper plate (not installed).

Mine sits right behind the stove on the rear-exit single-wall pipe. If you have double-wall, they do make damper setups for that - just a little more expensive. The plate itself is usually designed to restrict airflow without shutting it off entirely - you'll make about 80% restriction at best. I can really hear the gas flow thru the stove inlet and exhaust slow down considerably when I shut the damper.

 

[Vic99]

Czarcar says: "she has 30’ chimney, could heat be getting sucked up by excess draft?"

I also have a tall chimney like that and believe that is part of my problem . . . although my stove top temps are much better, except when the wood is wet. I will also install a damper this summer when I reconfigure my set up or get a new stove.

Looking foward to seeing how much a damper increases burn time for the overnight.

 

[edthedawg]

I absolutely think that is what's happening - chimney is likely >30' and that's sucking the heat out too fast. I also think the general burning (and possibly loading, too) practices can have something to do with it. Seeing the fire go to full roaring flame can be a bit shocking. Leaving it there for 15 minutes can seem downright insane - until you realize that it doesn't hurt anything, and actually helps establish the desired heat.

Plus the strong burn has the beneficial effect of baking out the nastiness that can accumulate in the pipe. Adding a damper will reduce flue temps when it is closed, which increases creosote buildup. Burning it out every day helps offset that buildup.

I also agree w/ your suggestion - the air control on the front is NOT a damper. Despite many folks referring to closing down the primary as "dampering down" - that's not what you're doing. You're cutting primary intake air...

 

[edthedawg]

I got pulled away mid-post last time... One quick thing on loading practices. You need to give the flames and air room to move thru the load, but not too much. My wife is great at making these smouldering piles of charred, glossy, unburned wood in the back of the stove w/ 250F stovetop temps. She claims she left the primary and flue damper both open for an hour, then shut them... Bottom line is the wood is just packed too tight and not enough access is given to the front - having all the fire in the back of the stove is just going to maintain low temps - you need strong fire presence up front.

I go in, reopen the flue damper, flip those pieces upside down and push them to the front (they're already flaming up more than they were at this point), throw a couple bark / kindling scraps on top, then some more splits & an EcoFirelog on top of that. Hold the side door about 1/2" open for about 30-60 seconds to fan the flames, then shut the door, leaving the primary and flue damper open - continue as above (get to full flame, leave 15m, back down, then shut down).

Remember too - from cold or dormant coals, it'll frequently be the SECOND load that really throws the big heat...

 

[Dottie]

So, smaller splits of wood dry as possible and not too tightly packed at first, but after it starts a secondary burn you can put in larger pieces. A damper (no matter what the chimney guy says) and leave it open to start the fire then partially close it after the fire gets going, and then close partway to lessen the draft? At the same time after the secondary burn starts close the primary air in increments?

If this the gist of it? Also, the liner is double lined.

And as always, thank you all for generously sharing your expertise.

 

[edthedawg]

Dottie - sounds about right. The damper can't hurt - if you set it flat in the pipe, it provides no restriction to flow. You can't really shove a brush thru it anyways w/ your setup - you're gonna have to pull the little horizontal stub out for cleaning anyways... If I roast my damper to smithereens (I suspect I am doing so) it's a cheap annual replacement for the benefit it brings...

I'm actually thinking of putting together a little movie file, showing the startup coals, raking & loading, and then the different settings, flame conditions, temps and timestamps...

And rounds of any size are tough to burn. I don't like to burn even 3" dia. maple rounds - I'll still split 'em down. I won't hesitate to burn big chunks of oak - but I do make sure to kickstart them with a very strong fire to begin the burn...

 

[Dottie]

Czarcar, I have watched that video, but with experience it might pay to watch it again. Funny, but I've found the more you know the more you get out of things sometime.

And Edthedawg, do you know somewhere I can see what you mean about damper installation? I have a hard time picturing it in my mind. it would be super if you included damper installation in your movie file. I bet it would be gratefully watched by lots of people learning about stoves new users such as myself, and people wanting to get more out of their stoves. I don't know how to describe my setup, but maybe I can try and take a picture and then download it. I'm technically challenged, but I do have a video camera and a computer at home, although it's dialup and I can go take a bath while waiting for a page to load!

Thanks, both of you for your help.

 

[edthedawg]

Dottie,

Here's a link showing a Simpson Duravent pre-installed damper section.

https://www.dynamitebuys.com/store/secure/images/products/1025_large5.jpg
http://www.dynamitebuys.com/store/cart.php?m=product_detail&p=1025

I don't know if you have Simpson Duravent or not. My single-wall pipe out the back was more or less a flat sheetmetal section w/ a locking seam that wrapped around the plate (similar to the one I showed above). Just had to remove the handle to slip it thru the hole in the side of the pipe.